Suspension thrust bearing unit

Abstract

To provide a suspension thrust bearing unit with an improved labyrinth seal that suppresses rotational friction and optimizes sealing performance, is easy to manufacture, and is economical. [Solution] The present invention relates to a suspension thrust bearing unit (1) for use in an automobile suspension assembly. The unit comprises a bearing (5) having an upper ring (50) mounted inside an upper annular cap (3), a lower ring (51) mounted inside a lower annular cap (4), and at least one row of rolling elements (52) arranged between raceway surfaces defined by the lower ring (51) and the upper ring (50). The lower annular cap (4) comprises at least one annular circumferential groove (60;64), and the upper cap (3) comprises an annular skirt (32) thereby forming a curved chamber defining a labyrinth seal means (6). According to the present invention, the groove (60;64) comprises a plurality of ribs (65;66).

Description

Technical Field

[0001] The present invention relates particularly to the field of MacPherson type suspension thrust bearing units. Such suspension thrust bearing units are provided in a suspension assembly for use in motor vehicles.

Background Art

[0002] Generally, an automotive suspension system includes a suspension assembly that supports an axle and wheels. The suspension thrust bearing unit is disposed above the suspension assembly, on the opposite side of the wheel and the ground, and between a suspension spring and an upper support block mounted to the vehicle body.

[0003] This suspension thrust bearing unit includes at least one rolling bearing.

[0004] The suspension thrust bearing unit enables the transmission of an axial force between the spring and the vehicle body, while allowing relative angular movement between the spring, which is movable in the rotational direction, and a fixed support block mounted to the vehicle body.

[0005] For this purpose, the spring is supported by a spring seat provided on the suspension thrust bearing unit. More precisely, this suspension thrust bearing unit includes a lower support surface that is placed on the end coil of the spring. The spring support surface includes a radial surface for supporting an axial force. The spring support surface may also include a tubular axial surface for providing support against radial deformation and ensuring centering of the spring.

[0006] Suspension thrust bearing units are used in environments where they are constantly exposed to contaminants, particularly dust, particles, and water. EP1000781, US6186507, WO07 / 037308 disclose examples of suspension thrust bearing units, the suspension thrust bearing units comprising sealing means for preventing the ingress of contaminants into the unit. The sealing means comprises a contact lip. However, such sealing means are not entirely satisfactory because they generate friction in the relative rotational direction between the two parts of the unit.

[0007] Furthermore, it is known from WO2010 / 063305 or JP 2006-322505 that labyrinth seals are provided in which the two parts do not have contact points during relative rotation. Friction is reduced, but it is necessary to optimize the sealing function, especially against heavy contamination and, in particular, against water jets. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] European Patent No. 1000781 [Patent Document 2] U.S. Patent No. 6186507 [Patent Document 3] International Publication No. 07 / 037308 brochure [Patent Document 4] International Publication No. 2010 / 063305 Pamphlet [Patent Document 5] Japanese Patent Publication No. 2006-322505 [Overview of the project] [Problems that the invention aims to solve]

[0009] The objective of the present invention is to provide a suspension thrust bearing unit having an improved labyrinth seal that suppresses rotational friction and optimizes sealing performance, is easy to manufacture, and is economical. [Means for solving the problem]

[0010] For this purpose, the present invention relates to a suspension thrust bearing unit used in an automobile suspension assembly. The suspension thrust bearing unit comprises a bearing having an upper ring mounted inside an upper annular cap, a lower ring mounted inside a lower annular cap, and at least one row of rolling elements arranged between the raceway surfaces defined by the lower and upper rings. The lower and upper annular caps are provided with sealing means to prevent contaminants from entering the unit.

[0011] The lower annular cap includes at least one annular circumferential groove provided between a first seal flange and a second seal flange extending radially outward from the lower cap. The upper annular cap includes an annular outward skirt extending axially from the upper cap toward the lower cap, wherein at least one of the seal flanges of the lower cap is radially surrounded by the skirt. The groove, the flanges, and the skirt form a curved chamber defining a labyrinth seal means.

[0012] According to the present invention, the annular circumferential groove comprises a plurality of ribs. The ribs are spaced apart in the circumferential direction within the groove. The ribs extend radially outward from the lower cap, are defined axially between the first seal flange and the second seal flange, and are at least partially surrounded radially by the skirt.

[0013] The present invention provides a sealed interior for the suspension thrust bearing unit, protecting it from the ingress of dust, particles, and water from the outside. The radial flanges form a physical barrier against water jets that spray substantially axially or obliquely from the bottom of the vehicle toward the suspension thrust bearing unit. The use of multiple radial flanges allows for the sequential blocking of contaminants that have passed through the previous flange. The axial skirt of the upper cap surrounds the flanges, ensuring protection against radial spraying of contaminants. The labyrinth sealing means of the present invention reliably improves watertightness in the axial, radial, and oblique directions. The series of sealing means makes it possible to reduce the amount of contaminants after each sealing means.

[0014] Furthermore, the multiple ribs can block contaminants from flowing into the labyrinth seal. More precisely, these ribs form axially spaced circumferential walls within the groove, while the flanges form radial walls. The flanges prevent contaminants from entering the groove, and the ribs restrict the movement of contaminants within the groove. This significantly improves the efficiency of the labyrinth seal.

[0015] The sealing function is designed to reduce friction by eliminating contact elements between the lower and upper caps during relative rotation.

[0016] The lower and upper rings of the bearing define the internal space in which the rolling elements are arranged. The lower and upper rings are mounted inside the lower and upper caps of the unit, respectively, and a curved chamber is defined between the caps. The curved chamber forms an extension from the internal space within the bearing. This configuration allows for the addition of a lubricant, such as lubricating grease, to this internal space after the unit has been installed.

[0017] According to a further aspect of the present invention, which is advantageous but not essential, such a suspension thrust bearing unit may incorporate one or more of the following features: - The inner and outer rings are made from stamped metal plates. - The upper and lower caps may optionally be made from a rigid plastic material such as polyamide, reinforced with glass fibers. - The upper cap and / or lower cap may be equipped with stiffening inserts. - The bearing consists of a rolling bearing, in which an inner ring and an outer ring define an annular rolling chamber between them, and at least one row of rolling elements is disposed within the rolling chamber. - The rolling element is a ball. - The lower annular cap may be equipped with a dedicated damping device to form a seat for the suspension spring. - The lower annular portion is equipped with an axial hub, and the first flange extends radially outward from the hub. - The damping device comprises a portion covering the lower radial surface of the first radial flange, and the damping device is dedicated to forming a seat for the suspension spring. - The damping device comprises a portion that covers the outer cylindrical surface of the hub, and the said portion of the damping device is dedicated to supporting radial loads from the suspension spring. - The damping device comprises a radial flange projecting radially outward from a first flange of the lower annular cap. - Damping devices are made from elastic materials such as rubber, particularly thermoplastic polyurethane (TPU), thermoplastic elastomers (TPE), melt-processable elastomers (MPE), or cellular polyurethane. - The first seal flange extends radially beyond the second seal flange of the lower annular cap. - The axial skirt of the upper annular cap circumferentially surrounds the second seal flange of the lower annular cap in the radial direction and is axially oriented toward the first flange of the lower annular cap. - The lower cap includes a plurality of annular circumferential grooves, each annular circumferential groove being defined between the upper seal flange and the lower seal flange. - The lower annular cap includes a third flange extending radially outward from the cap, an annular circumferential groove being defined between the second seal flange and the third seal flange, and the third flange being surrounded in the radial direction by the axial skirt of the upper annular cap. - The second seal flange extends radially beyond the third seal flange of the lower annular cap. - Each annular circumferential groove includes circumferentially spaced ribs, the ribs extending radially outward from the lower cap and being axially defined between the seal flanges defining the corresponding outer circumferential groove and being at least partially surrounded in the radial direction by the skirt. - The upper annular cap includes a second axial skirt extending axially from the cap toward the second flange of the lower annular cap, the second axial skirt circumferentially surrounding the third flange of the lower annular cap in the radial direction, and the second axial skirt being surrounded in the radial direction by the first axial skirt of the upper annular cap. - The ribs are circumferentially equally spaced apart. - The ribs of the separate annular circumferential grooves are circumferentially aligned with each other.

[0018] Hereinafter, the present invention will be exemplarily described with reference to the accompanying drawings, which do not limit the scope of the present invention.

Brief Description of the Drawings

[0019] [Figure 1] It is a plan view of a suspension thrust bearing unit. [Figure 2] It is a perspective view of the lower cap for the unit of FIG. 1. [Figure 3]This is a first axial half-cross-sectional view of the unit shown in Figure 2 according to the present invention. [Figure 4] This is a second axial half-cross-sectional view of the unit shown in Figure 2 according to the present invention. [Modes for carrying out the invention]

[0020] A suspension thrust bearing unit 1 having a central axis X1 is mounted between a helical suspension spring (not shown) and a support block (not shown) connected to the chassis of an automobile. Such a suspension thrust bearing unit 1 can be used, for example, in an automobile's MacPherson strut assembly.

[0021] Hereafter, the adjectives "axial" and "radial" are defined with respect to the central axis X1 of the annular suspension thrust bearing unit 1.

[0022] The suspension thrust bearing unit 1 comprises an upper cap 3, a lower cap 4, and a single rolling bearing 5. These three components 3, 4, and 5 have an overall circular shape around a central axis X1.

[0023] The upper cap 3 is a one-piece component made from a synthetic plastic material such as polyamide, which is optionally reinforced with glass fibers. The upper cap 3 has an upper radial portion 30, a relatively small-diameter inner annular skirt 31 extending toward the lower side of the suspension thrust bearing unit 1, and a relatively large-diameter outer annular skirt 32 extending toward the lower side of the suspension thrust bearing unit 1.

[0024] The upper cap 3 is specifically designed to be fixed to a support block (not shown) of the automobile chassis.

[0025] The rolling bearing 5 comprises an inner raceway 50 made of pressed sheet metal, an outer raceway 51 also made of pressed sheet metal, a row of rolling elements 52 which are balls, and a cage 53 for maintaining a constant circumferential spacing between the rolling elements 52. The rolling elements 52 are arranged between the raceway surfaces formed by the toroidal portions of the inner raceway 50 and the outer raceway 51. As an alternative example not shown, the rolling elements may be rollers.

[0026] The rolling bearing 5 is integrally arranged radially between the inner skirt 31 and the outer skirt 32 of the upper cap 3. The inner raceway 50 is fitted into the toroidal inner portion of the upper cap 3. The outer raceway 51 is fitted onto the toroidal outer portion of the lower cap 4.

[0027] The lower cap 4 includes a hub 41 defining an inner bore 42. The inner skirt 31 defines an inner bore 33 for the suspension thrust bearing unit 1, and an elongated shock absorber rod (not shown) is mounted within the bores 33, 42. The inner skirt 31 of the upper cap 3 includes a plurality of outwardly projecting clips 34 oriented toward the hub 41 of the lower cap 4. The lower cap includes inwardly projecting clips 44 oriented toward the skirt 31. The clips 34 extend at a limited angle, while the clips 44 are annular. The cooperation of the clips 34, 44 ensures axial assembly of the upper cap 3 and the lower cap 4. Each of the clips 34, 44 has a truncated conical surface to facilitate assembly of the caps 3, 4.

[0028] Furthermore, the lower cap 4 includes an outwardly projecting radial flange 43 that extends from the hub 41 toward the outside of the suspension thrust bearing unit 1.

[0029] The toroidal outer portion that supports the outer raceway 51 of the rolling bearing 5 is provided on the upper surface of the radial flange 43.

[0030] The hub 41 of the lower cap 4 can support radial loads and impacts from the suspension spring and can also dampen vibrations.

[0031] The lower cap 4 and the upper cap 3 further include sealing means 6 for preventing contaminants from entering the internal space defined between the caps 3 and 4 and between the rings 50 and 51 of the bearing 5.

[0032] According to the present invention, the sealing means 6 consists of a labyrinth seal designed as follows.

[0033] The lower annular cap 4 includes a first annular circumferential groove 60 provided between a first seal flange 61 and a second seal flange 62 that extend radially outward from the lower cap 4. More precisely, the seal flanges 61 and 62 form an annular shape along the direction of their parallel radial extensions. The first seal flange is the radially outward extension of the radial flange 43 of the lower cap 4. The second seal flange 62 is axially shifted from the first seal flange 61 toward the upper cap 3, thereby defining the outward circumferential groove 60.

[0034] Advantageously, the first flange 61 extends radially beyond the second flange 62 of the lower annular cap 4.

[0035] The upper annular cap 3 includes an annular outer skirt 32 that extends axially from the upper cap 3 toward the lower cap 4. The second flange 62 of the lower cap 4 is radially surrounded by the skirt 32. In this embodiment, the skirt 32 is oriented toward the cap flange 43, and the ends of the skirt 32 face radially toward the first seal flange 61 and axially toward the second seal flange 62. The groove 60, flanges 61, 62, and skirt 32 form a curved chamber defining the labyrinth seal means 6.

[0036] As an alternative example not shown, the skirt 32 may surround the first flange 61 in the radial direction.

[0037] The radially extending first seal flange 61 forms a first axial stopper against contaminants, which is particularly for blocking axial and oblique jets of water or dust. The second flange 62 forms a second axial stopper against contaminants, which is particularly for blocking any remaining contaminants not blocked by the first flange 61. The groove 60 directs the remaining contaminants from the second flange to the first flange. The skirt 32 forms a radial stopper against contaminants. Furthermore, the skirt 32 also allows for redirection of contaminants blocked by the second flange 62 to the outside of unit 1. The gaps between the first flange 61 and the skirt 32 and between the second flange 62 and the skirt 31 are reduced to limit the amount of contaminant that can enter between the lower cap and the upper cap, while preventing contact. The bearing 5 prevents rotational friction during relative rotation between caps 3 and 4.

[0038] Advantageously, the lower annular cap 4 includes a third seal flange 63 extending radially outward from the cap 4. This third seal flange 63 is annular along the direction of the radial extension parallel to the first flange 61 and the second flange 62. The third seal flange 63 is axially shifted from the second seal flange 62 toward the upper cap 3, thereby defining a second outward circumferential groove 64.

[0039] The third flange 63 is surrounded by the axial skirt 32 of the upper annular cap 3.

[0040] Advantageously, the second flange 62 extends radially beyond the third flange 63 of the lower annular cap 4.

[0041] Advantageously, the upper annular cap 3 includes a second axial skirt 35 that extends axially from the cap 3 toward the second flange 62 of the lower annular cap 4. The second axial skirt 35 radially surrounds the third flange 63 of the lower annular cap 4, and the second axial skirt 35 is radially surrounded by the first axial skirt 31 of the upper annular cap 3. An annular groove 36 is defined between the first skirt 31 and the second skirt 35 of the annular cap 3.

[0042] A radially extending third seal flange 63 forms a third axial stopper for contaminants, specifically for blocking any remaining contaminants not blocked by the first seal flange 61 and the second seal flange 62. A groove 64 directs the remaining contaminants from the second flange to the third flange. The skirt 35 allows the contaminants blocked by the third flange 63 to be redirected to the outside of unit 1. A groove 36 allows the redirected contaminants to be blocked as they pass through the second flange 62. The gaps between the second flange 62 and the skirt 35, and between the third flange 63 and the skirt 35, are reduced to prevent contact while further limiting the entry of contaminants between the lower cap and the upper cap. This design forms a multi-labyrinth seal for the unit.

[0043] According to the present invention, both the first annular circumferential groove 60 and the second annular circumferential groove 64 are provided with a plurality of ribs 65, 66, respectively.

[0044] The first annular circumferential groove 60 comprises a first series of ribs 65. These ribs 65 are spaced equally apart in the circumferential direction within the groove 60. The ribs 65 extend radially outward from the lower cap 4 and are defined axially between the first seal flange 61 and the second seal flange 62.

[0045] The second annular circumferential groove 64 comprises a second series of ribs 66. These ribs 66 are spaced equally apart in the circumferential direction within the groove 64. The ribs 66 extend radially outward from the lower cap 4 and are defined axially between the second seal flange 62 and the third seal flange 63.

[0046] In the illustrated example, the ribs 65 and 66 of the annular circumferential grooves 60 and 64 are aligned with each other in the circumferential direction.

[0047] In an alternative embodiment, only one of the two grooves 60, 64 is provided with a series of ribs. According to another embodiment, the lower cap 4 is provided with three or more annular circumferential outer grooves, each of which is provided with a series of ribs.

[0048] Multiple ribs 65, 66 enable the blocking of contaminants from flowing into the labyrinth seal 6. More precisely, the ribs 65, 66 form circumferentially spaced axial walls within the grooves 60, 64, while the seal flanges 61, 62, 63 form radial walls. The flanges 61, 62, 63 prevent contaminants from entering the grooves 60, 64, and the ribs 65, 66 restrict the movement of contaminants within the grooves 60, 64. In this way, the efficiency of the labyrinth seal 6 is greatly improved.

[0049] In alternative examples not shown, the lower cap 4 may include a damping device made from an elastic material such as rubber, particularly thermoplastic polyurethane (TPU), thermoplastic elastomer (TPE), melt-processable elastomer (MPE), or cellular polyurethane. This damping device may be located on the underside of the lower cap 4 to support and dampen a spring.

[0050] The above describes in detail representative and non-limiting examples of the present invention with reference to the accompanying drawings. This detailed description is intended solely to teach those skilled in the art further details for carrying out preferred embodiments of the present teachings and is not intended to limit the scope of the present invention. Furthermore, any additional features and teachings disclosed above may be used separately or in combination with other features and teachings to provide improved suspension thrust bearing units.

[0051] Furthermore, various features of the representative examples described above, as well as the various independent and dependent claims below, may be combined in ways not specifically and explicitly enumerated to provide further useful embodiments of the present invention. [Explanation of Symbols]

[0052] 1. Suspension thrust bearing unit 3 Upper ring cap, upper cap 4. Lower annular cap, lower cap 5. Rolling bearings, bearings 6. Sealing means 30 Upper radial section 31 Inner annular skirt, first axial skirt 32 Annular Outer Skirt 33 Internal bore 34 Outward-projecting clip 35 Second axial skirt 36 Annular groove 41 Hub 42 Internal bore 43 Outward-projecting radial flange 44 Inwardly protruding clip 50 Inner raceway, upper ring 51 Outer raceway, lower ring 52 Rolling element 53 cages 60 First annular circumferential groove 61 First seal flange 62 Second seal flange 63 Third seal flange 64 Second annular circumferential groove 65 Rib 66 Ribs X1 center axis

Claims

1. A suspension thrust bearing unit (1) for use in an automobile suspension assembly, comprising a bearing (5) having an upper ring (50) mounted inside an upper annular cap (3), a lower ring (51) mounted inside a lower annular cap (4), and at least one row of rolling elements (52) arranged between the raceway surfaces defined by the lower ring (51) and the upper ring (50), wherein the lower annular cap (4) and the upper annular cap (3) are provided with sealing means (6) to prevent contaminants from entering the unit (1), and the lower annular cap (4) extends radially outward from the lower cap (4) In a suspension thrust bearing unit (1), the upper annular cap (3) is provided with at least one annular circumferential groove (60;64) between a first seal flange (61;62) and a second seal flange (62;63), the upper annular cap (3) is provided with an annular outer skirt (32) extending axially from the upper cap (3) toward the lower cap (4), at least one of the flanges (62;63) of the lower cap (4) is radially surrounded by the skirt (32), and the groove (60;64), the flanges (61, 62;63) and the skirt (32) form a curved chamber defining the labyrinth seal means (6), A suspension thrust bearing unit (1) characterized in that the annular circumferential groove (60;64) comprises a plurality of ribs (65;66), the ribs (65;66) being spaced apart circumferentially within the groove (60;64), extending radially outward from the lower cap (4), defined axially between the first seal flange and the second seal flange (61, 62;63), and at least partially surrounded radially by the skirt (32).

2. The unit according to claim 1, wherein the ribs (65;66) are spaced equally apart in the circumferential direction.

3. The unit according to claim 1 or 2, wherein the first flange (61) extends radially beyond the second flange (62) of the lower annular cap (4).

4. The unit according to claim 3, wherein the axial skirt (32) of the upper annular cap (3) radially surrounds the second flange (62) of the lower annular cap (4) and is axially oriented toward the first flange (61) of the lower annular cap (4).

5. The unit according to any one of claims 1 to 4, wherein the lower annular cap (4) comprises a third flange (63) extending radially outward from the cap (4), an annular circumferential groove (64) is defined between the second flange (62) and the third flange (63), and the third flange (63) is surrounded by the axial skirt (32) of the upper annular cap (3).

6. The unit according to claim 5, wherein the second flange (62) extends radially beyond the third flange (63) of the lower annular cap (4).

7. The unit according to claim 6, wherein the upper annular cap (3) comprises a second axial skirt (35) extending axially from the cap (3) toward the second flange (62) of the lower annular cap (4), the second axial skirt (35) radially surrounds the third flange (63) of the lower annular cap (4), and the second axial skirt (35) is radially surrounded by the first axial skirt (31) of the upper annular cap (3).

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